System for cooling gas turbine inlet air

ABSTRACT

A system includes a turbine air quality device. The turbine air quality device includes a liquid desiccant path configured to circulate a liquid desiccant through an air flow directed to a turbine inlet. The turbine air quality device also includes a porous media disposed in the liquid desiccant path, wherein the porous media is configured to pass the air flow in direct contact with the liquid desiccant.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to a system and method for cooling gas turbine inlet air.

A gas turbine engine combusts a mixture of fuel and air to drive one or more turbine stages. As appreciated, the gas turbine engine generally intakes ambient air into a compressor, which compresses the air to a suitable pressure for optimal combustion of the fuel in a combustor. Unfortunately, the temperature and humidity of the ambient air can vary significantly due to geographic location, seasons, and so forth. The humidity in the air can be detrimental to components of the gas turbine engine. For example, the humidity can increase corrosion and icing in the gas turbine compressor. In addition, the temperature of the ambient air can reduce performance of the gas turbine engine. As a result, control of the temperature and humidity of air into the gas turbine engine can greatly improve performance and lifetime of the gas turbine engine.

BRIEF DESCRIPTION OF THE INVENTION

Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

In a first embodiment, a system includes a turbine air quality device, including a liquid desiccant path configured to circulate a liquid desiccant through an air flow directed to a turbine inlet, and a porous media disposed in the liquid desiccant path, wherein the porous media is configured to pass the air flow in direct contact with the liquid desiccant.

In a second embodiment, a system includes an air cooler, including an airpath, a heat exchanger configured to cool a liquid desiccant, and a chiller configured to receive the liquid desiccant and to flow the liquid desiccant into direct contact with the airpath, wherein the liquid desiccant is configured to cool and remove moisture from air in the airpath.

In a third embodiment, a system includes a media chiller, including an airpath, a liquid desiccant path, and a porous media disposed in both the airpath and the liquid desiccant path in the media chiller, wherein the porous media is configured to enable direct contact between air in the airpath and liquid dessicant in the liquid desiccant path.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic block diagram of an embodiment of an integrated gasification combined cycle (IGCC) power plant with an air cooling unit in accordance with an embodiment;

FIG. 2 is a block diagram of the air cooling unit and gas turbine engine, as illustrated in FIG. 1, in accordance with an embodiment;

FIG. 3 is a diagram of a chiller of the air cooling unit, as illustrated in FIG. 2, in accordance with an embodiment; and

FIG. 4 is a graphical representation of operation of the air cooling unit, as illustrated in FIG. 1, in accordance with an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

As discussed in detail below, the disclosed embodiments are directed to a system and method that chills gas turbine inlet air with a liquid desiccant cycle. In particular, the disclosed embodiments may employ a direct contact media-type moisture absorber/chiller using a liquid desiccant cycle, rather than indirect contact heat exchangers (e.g., working fluid isolated inside coils), evaporative coolers, mechanical chillers, absorption chillers, and thermal energy storage systems. The system has at least one loop for chilled liquid desiccant to absorb heat and moisture from turbine inlet airflow, resulting in the air condition of a dry bulb temperature substantially lower than the ambient and a relative humidity noticeably less than 100%. The heat and mass transfer process occurs when the inlet air penetrates a direct contact chiller, which may be installed downstream of one or more turbine inlet air filters.

Chilled liquid desiccant is brought into direct contact with air moving through an airpath in a chiller. This causes the liquid desiccant to absorb water from the air and to become diluted with water. Additionally, the direct contact of the chilled liquid desiccant with the air causes a heat transfer that cools the air and heats the liquid desiccant. The desiccant and water is separated from the air via a media, (such as a porous media), and the desiccant and water is accumulated in a sump of the chiller. After the diluted and heated liquid desiccant reaches the sump, it is pumped to at least one cooling heat exchanger to discharge the absorbed heat, reducing the liquid desiccant temperature back to its pre-set level for recirculation to the inlet air chiller. To maintain a desired desiccant concentration, the system is equipped with at least one regeneration loop that receives a by-pass flow of the diluted and heated liquid desiccant, raises its temperature through at least one heater, and then forces the liquid desiccant to release the captured moisture using an evaporator. The regenerated liquid desiccant is fed back to the chiller sump. To be energy efficient, the heater may use the heat recovered from gas turbine exhaust or other available heat sources such as turbine enclosure vent discharge.

FIG. 1 is a diagram of an embodiment of an integrated gasification combined cycle (IGCC) system 100 that may produce and bum a synthetic gas, i.e., syngas. As discussed below, the system 100 may employ one or more air cooling units (e.g., 133) utilizing a direct contact media-type moisture absorber/chiller with a liquid desiccant cycle, wherein each air cooling unit may be configured to simultaneously reduce the temperature and humidity of the air. The following discussion is intended to provide context for possible applications of the disclosed air cooling units. Elements of the IGCC system 100 may include a fuel source 102, such as a solid feed, that may be utilized as a source of energy for the IGCC. The fuel source 102 may include coal, petroleum coke, biomass, wood-based materials, agricultural wastes, tars, coke oven gas and asphalt, or other carbon containing items.

The solid fuel of the fuel source 102 may be passed to a feedstock preparation unit 104. The feedstock preparation unit 104 may, for example, resize or reshaped the fuel source 102 by chopping, milling, shredding, pulverizing, briquetting, or palletizing the fuel source 102 to generate feedstock. Additionally, water, or other suitable liquids may be added to the fuel source 102 in the feedstock preparation unit 104 to create slurry feedstock. In other embodiments, no liquid is added to the fuel source, thus yielding dry feedstock.

The feedstock may be passed to a gasifier 106 from the feedstock preparation unit 104. The gasifier 106 may convert the feedstock into a syngas, e.g., a combination of carbon monoxide and hydrogen. This conversion may be accomplished by subjecting the feedstock to a controlled amount of steam and oxygen at elevated pressures, e.g., from approximately 20 bar to 85 bar, and temperatures, e.g., approximately 700 degrees Celsius to 1600 degrees Celsius, depending on the type of gasifier 106 utilized. The gasification process may include the feedstock undergoing a pyrolysis process, whereby the feedstock is heated. Temperatures inside the gasifier 106 may range from approximately 150 degrees Celsius to 700 degrees Celsius during the pyrolysis process, depending on the fuel source 102 utilized to generate the feedstock. The heating of the feedstock during the pyrolysis process may generate a solid, (e.g., char), and residue gases, (e.g., carbon monoxide, hydrogen, and nitrogen). The char remaining from the feedstock from the pyrolysis process may only weigh up to approximately 30% of the weight of the original feedstock.

A combustion process may then occur in the gasifier 106. The combustion may include introducing oxygen to the char and residue gases. The char and residue gases may react with the oxygen to form carbon dioxide and carbon monoxide, which provides heat for the subsequent gasification reactions. The temperatures during the combustion process may range from approximately 700 degrees Celsius to 1600 degrees Celsius. Next, steam may be introduced into the gasifier 106 during a gasification step. The char may react with the carbon dioxide and steam to produce carbon monoxide and hydrogen at temperatures ranging from approximately 800 degrees Celsius to 1100 degrees Celsius. In essence, the gasifier utilizes steam and oxygen to allow some of the feedstock to be “burned” to produce carbon monoxide and release energy, which drives a second reaction that converts further feedstock to hydrogen and additional carbon dioxide.

In this way, a resultant gas is manufactured by the gasifier 106. This resultant gas may include approximately 85% of carbon monoxide and hydrogen in equal proportions, as well as CH₄, HCl, HF, COS, NH₃, HCN, and H₂S (based on the sulfur content of the feedstock). This resultant gas may be termed dirty syngas, since it contains, for example, H₂S. The gasifier 106 may also generate waste, such as slag 108, which may be a wet ash material. This slag 108 may be removed from the gasifier 106 and disposed of, for example, as road base or as another building material. To clean the dirty syngas, a gas cleaning unit 110 may be utilized. The gas cleaning unit 110 may scrub the dirty syngas to remove the HCl, HF, COS, HCN, and H₂S from the dirty syngas, which may include separation of sulfur 111 in a sulfur processor 112 by, for example, an acid gas removal process in the sulfur processor 112. Furthermore, the gas cleaning unit 110 may separate salts 113 from the dirty syngas via a water treatment unit 114 that may utilize water purification techniques to generate usable salts 113 from the dirty syngas. Subsequently, the gas from the gas cleaning unit 110 may include clean syngas, (e.g., the sulfur 111 has been removed from the syngas), with trace amounts of other chemicals, e.g., NH₃ (ammonia) and CH₄ (methane).

A gas processor 116 may be utilized to remove residual gas components 117 from the clean syngas such as, ammonia and methane, as well as methanol or any residual chemicals. However, removal of residual gas components 117 from the clean syngas is optional, since the clean syngas may be utilized as a fuel even when containing the residual gas components 117, e.g., tail gas. At this point, the clean syngas may include approximately 3% CO, approximately 55% H₂, and approximately 40% CO₂ and is substantially stripped of H₂S. This clean syngas may be transmitted to a combustor 120, e.g., a combustion chamber, of a gas turbine engine 118 as combustible fuel. Alternatively, the CO₂ may be removed from the clean syngas prior to transmission to the gas turbine engine.

The IGCC system 100 may further include an air separation unit (ASU) 122. The ASU 122 may operate to separate air into component gases by, for example, distillation techniques. The ASU 122 may separate oxygen from the air supplied to it from a supplemental air compressor 123, and the ASU 122 may transfer the separated oxygen to the gasifier 106. Additionally the ASU 122 may transmit separated nitrogen to a diluent nitrogen (DGAN) compressor 124.

The DGAN compressor 124 may compress the nitrogen received from the ASU 122 at least to pressure levels equal to those in the combustor 120, so as not to interfere with the proper combustion of the syngas. Thus, once the DGAN compressor 124 has adequately compressed the nitrogen to a proper level, the DGAN compressor 124 may transmit the compressed nitrogen to the combustor 120 of the gas turbine engine 118. The nitrogen may be used as a diluent to facilitate control of emissions, for example.

As described previously, the compressed nitrogen may be transmitted from the DGAN compressor 124 to the combustor 120 of the gas turbine engine 118. The gas turbine engine 118 may include a turbine 130, a drive shaft 131 and a compressor 132, as well as the combustor 120. The combustor 120 may receive fuel, such as syngas, which may be injected under pressure from fuel nozzles. This fuel may be mixed with compressed air as well as compressed nitrogen from the DGAN compressor 124, and combusted within combustor 120. This combustion may create hot pressurized exhaust gases.

The combustor 120 may direct the exhaust gases towards an exhaust outlet of the turbine 130. As the exhaust gases from the combustor 120 pass through the turbine 130, the exhaust gases force turbine blades in the turbine 130 to rotate the drive shaft 131 along an axis of the gas turbine engine 118. As illustrated, the drive shaft 131 is connected to various components of the gas turbine engine 118, including the compressor 132.

The drive shaft 131 may connect the turbine 130 to the compressor 132 to form a rotor. The compressor 132 may include blades coupled to the drive shaft 131. Thus, rotation of turbine blades in the turbine 130 may cause the drive shaft 131 connecting the turbine 130 to the compressor 132 to rotate blades within the compressor 132. This rotation of blades in the compressor 132 causes the compressor 132 to compress air received via an air intake in the compressor 132. The compressed air received via the air intake of the compressor 132 may be received from an air cooing unit 133 (e.g., an air cooler). The cooled air may then be compressed by the compressor 132, and the compressed air may be fed to the combustor 120 and mixed with fuel and compressed nitrogen to allow for higher efficiency combustion. Drive shaft 131 may also be connected to load 134, which may be a stationary load, such as an electrical generator for producing electrical power, for example, in a power plant. Indeed, load 134 may be any suitable device that is powered by the rotational output of the gas turbine engine 118.

As discussed in detail below, an embodiment of the air cooling unit 133, (i.e., turbine air quality unit) includes a direct contact media-type moisture absorber/chiller with a liquid desiccant cycle, wherein the air cooling unit 133 is configured to simultaneously reduce the temperature and humidity of the air. The reduced temperature and reduced humidity of the air may improve performance and lifespan of the gas turbine engine 118. For example, the reduced temperature may increase shaft power output by the gas turbine engine 118 and the reduced humidity may reduce the tendency for corrosion of components of the engine 118 due to moisture in the air. The air cooling unit 133 using a direct contact media-type moisture absorber/chiller with a liquid desiccant cycle cools well in both low and high humidity climates, rather than being limited to low humidity climates like evaporative coolers. By further example, an embodiment of the air cooling unit 133 using a direct contact media-type moisture absorber/chiller with a liquid desiccant cycle cools well with a simple media and direct contact with a liquid desiccant, rather than isolating a coolant in large coils of a heat exchanger which can be expensive and consumes a significant amount of space.

The IGCC system 100 also may include a steam turbine engine 136 and a heat recovery steam generation (HRSG) system 138. The steam turbine engine 136 may drive a second load 140. The second load 140 may also be an electrical generator for generating electrical power. However, both the first and second loads 134, 140 may be other types of loads capable of being driven by the gas turbine engine 118 and steam turbine engine 136. In addition, although the gas turbine engine 118 and steam turbine engine 136 may drive separate loads 134 and 140, as shown in the illustrated embodiment, the gas turbine engine 118 and steam turbine engine 136 may also be utilized in tandem to drive a single load via a single shaft. The specific configuration of the steam turbine engine 136, as well as the gas turbine engine 118, may be implementation-specific and may include any combination of sections.

The system 100 may also include the HRSG 138. Heated exhaust gas from the gas turbine engine 118 may be transported into the HRSG 138 and used to heat water and produce steam used to power the steam turbine engine 136. Exhaust from, for example, a low-pressure section of the steam turbine engine 136 may be directed into a condenser 142. The condenser 142 may utilize a cooling tower 128 to exchange heated water for chilled water. The cooling tower 128 acts to provide cool water to the condenser 142 to aid in condensing the steam transmitted to the condenser 142 from the steam turbine engine 136. Condensate from the condenser 142 may, in turn, be directed into the HRSG 138. Again, exhaust from the gas turbine engine 118 may also be directed into the HRSG 138 to heat the water from the condenser 142 and produce steam.

In combined cycle systems such as IGCC system 100, hot exhaust may flow from the gas turbine engine 118 and pass to the HRSG 138, where it may be used to generate high-pressure, high-temperature steam. The steam produced by the HRSG 138 may then be passed through the steam turbine engine 136 for power generation. In addition, the produced steam may also be supplied to any other processes where steam may be used, such as to the gasifier 106. The gas turbine engine 118 generation cycle is often referred to as the “topping cycle,” whereas the steam turbine engine 136 generation cycle is often referred to as the “bottoming cycle.” The combination of these engines may be a combined cycle engine 143. By combining these two cycles as illustrated in FIG. 1, the IGCC system 100 may lead to greater efficiencies in both cycles. In particular, exhaust heat from the topping cycle may be captured and used to generate steam for use in the bottoming cycle. The exhaust gas from the gas turbine engine may also be utilized in conjunction with the air cooling unit 133, as discussed below.

FIG. 2 is a schematic of an embodiment of the gas turbine engine 118 and the air cooling unit 133. While only a simple cycle gas turbine engine 118 is illustrated in FIG. 2 and described below, it should be noted that the air cooling unit 133 may be utilized with a simple cycle engine in conjunction with an IGCC system 100 or independent from an IGCC system 100. Similarly, the air cooling unit 133 may be applied to a simple cycle engine or a combined cycle engine 143 either in an IGCC system 100 or independent from an IGCC system 100. Indeed, the application of an air cooling unit 133 as set forth below, may be applied generally to any turbine system.

As previously discussed, the gas turbine engine 118 includes the combustor 120, the turbine 130, and the drive shaft 131 along an axis of the gas turbine engine 118, the load 134, and the compressor 132. The compressor 132 receives chilled air along path 144 from the air cooling unit 133. The cooling of this air may be accomplished via a chilling and dehumidifying process described below with respect to the air cooling unit 133.

As described above, the air cooling unit 133 may operate to cool air for transmission to the compressor 132. The air cooling unit 133 may accomplish this cooling process by passing air along a path 144 through a media chiller 146. The media chiller 146 may be a heat exchanger that removes heat from air passing along path 144 for introduction to the compressor 132. In the illustrated embodiment, the media chiller 146 allows a liquid desiccant to flow along one or more paths 148 through and/or along a surface of a media 150, thereby enabling the air flowing along path 144 to directly contact both the media 150 and the liquid desiccant. In addition, in some embodiments, the media chiller 146 may spray some of the liquid desiccant onto a surface of the media 150, while some or most of the liquid desiccant is routed directly into or along the surface of the media 150. However, some embodiments may exclude spraying of the liquid desiccant into the air flow, and instead may include flowing (or injecting) the liquid desiccant directly into and along the media 150 to reduce the possibility of the liquid desiccant being carried away with the air flow. In either case, the liquid desiccant is not isolated from the environment (e.g., the air flow) inside tubes or the like, but rather the media 150 enables the air flow to make direct contact between the air and the liquid desiccant either along an exterior surface or porous interior of the media 150.

In the disclosed embodiments, the liquid desiccant absorbs moisture and heat from the air in response to the direct contact between the air and liquid desiccant. As a result, the liquid desiccant may be described as a liquid desiccant solution due to the water content. For example, the liquid desiccant solution may be a hygroscopic solution (i.e., a substance that attracts water molecules from the surrounding environment through either absorption or adsorption) such as water and lithium chloride (H₂O/LiCl), water and lithium bromide (H₂O/LiBr), and water and potassium formate (H₂O/CHKO₂). That is, as the liquid desiccant (or liquid desiccant solution) directly contacts the air flowing along path 144, the liquid desiccant removes water from the air (i.e., lowers humidity) to increase the water content relative to the liquid desiccant. As discussed herein, the terms liquid desiccant and liquid desiccant solution may be used interchangeably, as the water content relative to the liquid desiccant content may continuously vary as moisture is collected by the liquid desiccant and then removed from the liquid desiccant.

The media 150 may be, for example, a porous corrugated or ridged plastic that contacts the air/desiccant solution. In other embodiments, graphite and/or metallic compounds may be utilized to form the media 150. The media 150 may be structured, such as in a crossflow pattern, or it may be unstructured. Regardless of the structure of the media 150, the media 150 provides a region for direct contact between air and the liquid desiccant solution. This region may be referred to as a direct interaction zone of air/liquid desiccant solution. In this direct interaction zone, the moisture in the air may condense onto the media 150 and then collect into the liquid desiccant solution and/or the moisture in the air may directly collect into the liquid desiccant solution. Thus, the liquid desiccant solution flowing along one or more paths 148 may capture at least some portion of the moisture in the air, while still allowing the air (less the collected moisture) to continue to flow along path 144 into the compressor 132. In certain embodiments, the direct interaction zone may reduce the humidity of the air by at least approximately 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, or 90 percent, while causing an increasing in water content in the liquid desiccant solution. In this manner, the moisture (e.g., water or humidity) is at least substantially stripped (i.e., separated) from the air passing through the media 150. Furthermore, as discussed further below, the air may substantially cooled by the liquid desiccant solution. For example, the liquid desiccant solution may be cooled to a temperature lower than the air, thereby enabling heat transfer away from the air into the liquid desiccant solution.

It should be noted that the media 150 may operate with either a fouled or filtered air. Accordingly, a filter 152 may be utilized upstream of the media 150 to remove airborne impurities before directly contacting the air with the liquid desiccant solution in and/or on the media 150. Alternatively, the filter 152 may be removed from the air cooling unit 133. Furthermore, the filter 152 may be integral to or distinct from the media chiller 146.

As described above, the liquid desiccant solution flow along the paths 148 while the air flows along the path 144. After collecting moisture from the air, the liquid desiccant solution (with increased water content) may collect in a sump 154, or bottom, of the media chiller 146. The liquid desiccant solution may be removed from the sump 154 by a pump 156 via line 158. The pump 156 may transmit the liquid desiccant solution to a bypass valve 160 via line 162. The bypass valve 160 may, for example, regulate the regeneration of the liquid desiccant as well as control the supply of the liquid desiccant to the media chiller 146. As such, the bypass valve 160 may channel a small portion, for example, approximately 5, 6, 7, 8, 9, or 10 percent of the liquid desiccant solution in line 162, into line 164 for transmission to a regeneration unit 166.

The regeneration unit 166 may be a separate unit from the media chiller 146. The regeneration unit 166 may, for example, automatically remove water from the liquid desiccant solution to maintain the desiccant at the proper concentration. That is, the regeneration unit 166 may operate to remove the water from the liquid desiccant solution to generate a concentrated liquid desiccant for use in the media chiller 146. In the regeneration unit 166, the liquid desiccant solution circulates through a heat exchanger 168. The heat exchanger 168 heats the liquid desiccant solution with heat flow 170 so that its water vapor pressure is substantially higher than that of the outside air 184. The heat flow 170 may be received from, for example, the exhaust of the turbine 130, or the regeneration unit 166 may employ other heat sources, such as boiler water, an electrical heater, and so forth. In one embodiment, the liquid desiccant solution may flow through tubing and/or coils of the heat exchanger 168 as indicated by the directional arrow 172. The heat flow 170 may contact the tubing in the heat exchanger 168 and, thus, may indirectly heat the liquid desiccant solution therein by heating the tubing. Alternatively, heat flow 170 may directly contact the liquid desiccant solution in the heat exchanger 168 to allow for direct heat exchange to occur. Regardless of the method of the heat exchange in the heat exchanger 168, heat is imparted to the liquid desiccant solution in the heat exchanger 168. The heat that is imparted to the liquid desiccant solution in the heat exchanger 168 facilitates the increase of the partial vapor pressure of the water in the liquid desiccant solution. Indeed, the water vapor pressure difference between the heated liquid desiccant solution and that of the outside (ambient) air 184 is the driver for the moisture removal, as will be discussed below.

The regeneration unit 166 passes the fluid from the heat exchanger 168 to a second heat exchanger 174, (e.g., a liquid desiccant cooler), which is configured to cool the fluid. The illustrated heat exchanger 174 may include a manifold 176 to distribute the fluid evenly to one or more injection units 178, which are configured to disperse the fluid into a core 180, which may include a packed bed contactor surface 182. As noted above, the heat exchanger heat 168 imparts heat to the liquid desiccant solution with heat flow 170 so that the water vapor pressure of the water in the liquid desiccant solution is substantially higher than that of the outside air 184. Outside air 184 is passed through the packed bed contactor surface 182, and water evaporates into the outside air 184 from the desiccant solution, thus concentrating the solution. The hot, moist air from the regeneration unit 166 is discharged with the outside air 184 and the now cooled and concentrated liquid desiccant may flow through the core 180 along directional lines 186 into the sump 188 of the heat exchanger 174. Accordingly, the sump 188 may be a collection location for the regenerated liquid desiccant. This liquid desiccant may then be transmitted to the sump 154 of the media chiller 146 via line 190. In sump 154, the liquid desiccant may mix with the liquid desiccant solution to enrich the overall ratio of liquid desiccant to water in the sump 154. It should be additionally noted that the water removal capacity of the regeneration unit 166 may be controlled to match the moisture load of the inlet of the compressor 132. This may be accomplished by regulating the heat flow 170 to the heat exchanger 168 to maintain a constant desiccant solution concentration.

As previously described, the liquid desiccant solution may be removed from the sump 154 via pump 156 via line 158. The pump 156 may transmit the liquid desiccant solution to a bypass valve 160 via line 162. The bypass valve 160 may control the supply of the liquid desiccant to the media chiller 146. As such, the bypass valve 160 may channel the liquid desiccant solution along line 192 to the media chiller 146 via the cooler 194.

The cooler 194 may be a cooling heat exchanger that operates to reduce the heat of the liquid desiccant solution. In this manner, the liquid desiccant solution transmitted to the media chiller 146 may be lower in temperature than the incoming air passing along path 144. Thus, as moisture is removed from the air passing through the media chiller 146, direct exposure of the air to the chilled liquid desiccant solution may act as a direct heat exchange to lower the overall temperature of the air passing through the media chiller 146 along path 144. The liquid desiccant solution that contacts the air flowing through the media chiller 146 along path 144 may be brought into contact with the air via a manifold 196 that may operate to distribute the liquid desiccant solution evenly to one or more injection units 198 of the media chiller 146. Additionally the manifold 196 disposed on a top portion of the media 150 may channel the liquid desiccant solution into an interior 199 of the media 150 via the injection units. That is, the injection units 198 may disperse (e.g., spray) the liquid desiccant solution into the media chiller 146 (e.g., into the interior of the media chiller) so that it can directly contact the air flowing along path 144 to both directly cool and remove moisture from the air, as described above. In this manner, chilled and dehumidified air may pass to the compressor 132, leading to greater shaft power output by the gas turbine engine 118 as well as reduced exposure of the components of the gas turbine engine 118 to corrosion via water vapors.

FIG. 3 is a diagram of an embodiment of the media chiller 146. As previously described, the media chiller 146 may operate to cool and dehumidify air for use with a compressor 138. As illustrated, warm air may flow into the media chiller 146 along directional lines 200. In the illustrated embodiment, the air flows into each of three sections 202, 204, and 206 of the media chiller 146. While three sections are illustrated, it should be noted that one or more sections may make up the entirety of the media chiller 146. Each of section 202, 204, and 206 includes a manifold 196 that may operate to distribute a desiccant rich solution evenly to one or more injection units 198 of the media chiller 146. The injection units 196 may disperse (e.g., spray or inject) desiccant rich solution into the media chiller 146 so that it can directly contact the air flowing along directional line 200 to both directly cool and remove moisture from the air. The manifold 196 may be supplied with desiccant via a line 208, which may, for example, be a pipe connected to cooler 194 of FIG. 2. Additionally, a secondary line 210 may be utilized to supply desiccant rich solution into the media chiller 146.

Secondary line 210 also may be, for example, a pipe connected to cooler 194 of FIG. 2. However, line 210 does not terminate with a manifold 196. Instead, line 210 may include injection ports 212 that may directly spray (or inject) a mist of desiccant rich solution into the media chiller 146 to contact the air passing through the media chiller along directional lines 200. That is, the injection ports 212 may spray the liquid desiccant into the air flow toward an inlet side 213 of the media 150. It should be noted that that lines 208 and 210 may be utilized in conjunction with one another to provide a more even disbursement of the desiccant rich solution to the air in the media chiller 146. Alternatively, either line 208 or 210 may be utilized singularly, for example, to reduce overall costs of the media chiller 146.

As liquid desiccant contacts moisture in the air flowing along directional arrows 200, the liquid desiccant collects water from the air and carries it away in the media 150. As previously noted, the media 150 provides a contact region to enable direct contact between the air and the liquid desiccant solution, while also providing a flow path to carry away the liquid desiccant solution after cooling and reducing humidity of the air. As appreciated, the liquid desiccant may be substantially cooled relative to the air, e.g., 10, 20, 30, 40, or 50 degrees Fahrenheit cooler than the air. Thus, the temperature differential may cause the humidity in the air to condense onto the media 150, wherein the liquid desiccant can collect the condensed water and carry it away. However, the temperature differential may also cause the humidity in the air to condense or collect directly onto the liquid desiccant, e.g., the droplets of the liquid desiccant spray and/or the flow of liquid desiccant in the media 150. Regardless, the liquid desiccant both cools the air flow, while also removing moisture from the air flow via direct air/liquid desiccant contact. In turn, the liquid desiccant solution (with collected moisture) flows through the media 150 away from the air flow, while the air flow continues away from the media 150. In this manner, the liquid desiccant solution substantially strips the humidity (e.g., water content) of the air passing through the media 150. The desiccant solution may collect in a pooling region 214 to be removed via line 216 into the sump 154 of the media chiller 146. From there, the water rich desiccant solution may be removed from the media chiller 146 via line 158 for recirculation/regeneration, as previously described.

The air, now reduced in water content as well as chilled from direct contact with the previously chilled desiccant solution, passes away from the media 150 along directional arrows 218. At this point, the air flowing along directional arrows 218 may encounter a mist eliminator 220 downstream of the media 150. The mist eliminator 220 may function to remove any excess vapor/spray (e.g., fluid) from the air passing along directional arrows 218 before transmission to the compressor 132. For example, the mist eliminator 220 may collect any residual liquid desiccant spray from the injection ports 212. The mist eliminator 220 may be, for example, a filter that restricts moisture from passing while allowing air to pass. Furthermore, it should be noted that the mist eliminator 220 may optionally be removed from the media chiller 146, based on the air velocities and the ability of the liquid desiccant and the media 150 to remove water from the air passing through the media chiller 146.

FIG. 4 is a graphical representation of the effects of utilizing an air cooler 133 described above. In particular, FIG. 4 graphically illustrates a comparison between the disclosed air cooler 133 versus alternative cooling techniques, thereby showing the improved performance attributed to the air cooler 133. In particular, plot 222 represents an evaporative cooling technique, plot 224 represents a chilling technique, and plot 226 represents a dehumidification and chilling technique in accordance with certain embodiments of the disclosed air cooler 133. Each of these plots 222, 224, and 226 originates at a common starting point 228 of approximately 100 degrees Fahrenheit, approximately 20 percent relative humidity, and approximately 0.008 specific humidity. As illustrated, these plot 222, 224, and 226 vary significantly from the common starting point 228 in terms of temperature and humidity. For example, the evaporative cooling plot 222 exhibits a drop in air temperature to approximately 75 degrees Fahrenheit, yet it also exhibits a substantial increase in relative humidity to over 60 percent and specific humidity to approximately 0.015. These increased humidity levels may cause the compressor 132 intake to ice over and the humidity levels may lead to corrosion of components of the gas turbine engine 118. The chilling plot 224 exhibits a drop in air temperature to approximately 50 degrees Fahrenheit with a substantial increase in relative humidity to approximately 90 percent. Although the chilling plot 224 indicates a generally constant specific humidity until approximately 60 degrees Fahrenheit, the specific humidity drops to approximately 0.007 at approximately 50 degrees Fahrenheit.

In contrast, through the combined use of direct contact with chilled desiccant and the media 150, as discussed above, the air passing through the air cooling unit 133 may undergo both dehumidification and cooling processes, as indicated by plot 226. The techniques described above with respect to the air cooling unit 133 may lead to the lowering of the temperature of the air to approximately less than 60 degrees Fahrenheit. While cooling the air to this temperature, the specific humidity of the air may be reduced to approximately 0.0025 while the relative humidity may remain at approximately 30 percent. Accordingly, through the use of chilled desiccant and media 150 in a media chiller 146, similar temperature drops to those experienced in air chillers may be replicated, but at lower humidity levels, thus leading to greater shaft power output for the gas turbine engine 118, as well as a reduction of corrosion due to inlet air moisture in the components of the gas turbine engine.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

1. A system, comprising: a turbine air quality device, comprising: a liquid desiccant path configured to circulate a liquid desiccant through an air flow directed to a turbine inlet; and a porous media disposed in the liquid desiccant path, wherein the porous media is configured to pass the air flow in direct contact with the liquid desiccant.
 2. The system of claim 1, wherein the liquid desiccant is configured to remove moisture from the air flow.
 3. The system of claim 2, wherein the liquid desiccant path comprises a sump configured to collect the liquid desiccant and a pump configured to return the liquid desiccant into the porous media.
 4. The system of claim 3, wherein the liquid desiccant path comprises a spray device configured to spray the liquid desiccant into the air flow toward an inlet side of the porous media.
 5. The system of claim 2, wherein the liquid desiccant path comprises a manifold disposed on a top portion of the porous media, and the manifold is configured to channel the liquid desiccant into an interior of the porous media.
 6. The system of claim 1, wherein the liquid desiccant path comprises a cooler configured to cool the liquid desiccant, and the liquid desiccant is configured to cool the air flow.
 7. The system of claim 1, comprising a liquid desiccant heater configured to heat the liquid desiccant after passing through the porous media, and a liquid desiccant cooler configured to cool the liquid desiccant after the liquid desiccant heater to remove water in the liquid desiccant.
 8. A system, comprising: an air cooler, comprising: an airpath; a heat exchanger configured to cool a liquid desiccant; and a chiller configured to receive the liquid desiccant and to flow the liquid desiccant into direct contact with the airpath, wherein the liquid desiccant is configured to cool and remove moisture from air in the airpath.
 9. The system of claim 8, comprising a media configured to flow the liquid desiccant through the airpath.
 10. The system of claim 9, wherein the media comprises a porous media configured to directly contact the liquid desiccant with the air in the airpath.
 11. The system of claim 9, comprising spray injector configured to spray the liquid desiccant onto the media.
 12. The system of claim 9, comprising a mist eliminator in the airpath downsteam of the media, wherein the mist eliminator is configured to remove fluid from the air in the airpath.
 13. The system of claim 9, comprising a liquid desiccant regenerator configured to remove moisture from the liquid desiccant.
 14. The system of claim 8, comprising a spray injector configured to spray the liquid desiccant into the airpath.
 15. The system of claim 8, comprising a sump configured to collect the liquid desiccant and a pump configured to pass the liquid desiccant from the sump to the liquid desiccant cooler.
 16. A system, comprising: a media chiller, comprising: an airpath; a liquid desiccant path; and a porous media disposed in both the airpath and the liquid desiccant path in the media chiller, wherein the porous media is configured to enable direct contact between air in the airpath and liquid dessicant in the liquid desiccant path.
 17. The system of claim 16, comprising a liquid desiccant regenerator configured to remove moisture from the liquid desiccant.
 18. The system of claim 16, comprising a spray injector configured to spray the liquid desiccant into the airpath or into the porous media.
 19. The system of claim 16, wherein the porous media comprises plastic, graphite, or a metallic compound.
 20. The system of claim 16, wherein the liquid desiccant comprises lithium chloride, lithium bromide, or potassium formate. 